Strengthen the circadian rhythms by the mathematical model of the SCN

The master clock, located in the suprachiasmatic nucleus, controls the circadian rhythms of mammals. Exposed to a natural light-dark cycle or under constant darkness, the circadian rhythms of the SCN are robust. Under special conditions, such as under constant light, after jet-lag and in aging, the rhythm is deteriorated due to being out of synchronization of the SCN neurons or the deteriorated rhythms in individual neurons. In the present article, we review the methods for strengthening the circadian rhythms (i.e., increasing the amplitude) of the SCN network based on the mathematical models, including the application of noise, the heterogeneity in the neuronal properties, and the heterogeneity in the network structure. These models shed light on the understanding the existence of heterogeneity in the SCN and provide alternatives to strengthen the SCN rhythm.